Antivirus software = good.
Clicking any "opt-out" links in porn spam email = usually a bad idea.
If you and others in your group of relatives and friends are receiving these same spam emails, there is a good chance that at least one person in your group has got a virus/trojan/worm on their PC.
http://en.wikipedia.org/wiki/Zombie_computer
Does everybody have antivirus software of some sort installed? Has anybody in the group seen any alerts about viruses being found and quarrantined recently? If so, *that person* may be clean, but they may be able to provide clues as to what virus you are dealing with, and by process of elimination, who among you doesn't need to be too concerned.
Here's a freebie online virus scanner from a reputable vendor:
http://housecall.trendmicro.com/
It's a good place to start for someone who doesn't have any antivirus software installed, or hasn't kept their antivirus software current.
If it reports that it finds something that it can't repair, you can take that information and Google it. Sometimes the major antivirus vendors release specialized "removal" utilities for specific viruses. If you see something like that from McAffee or Symantec (makers of Norton Antivirus) or Trend Micro, I will personally vouch for their integrity. :-)
Finally, if anyone in your group does not have antivirus software installed and needs something, but hates the thought of spending any money on it, a good freebie I recommend is:
http://www.grisoft.com/doc/289/lng/us/tpl/tpl01
Ohyeah, and regarding clicking on the "opt-out" links, in *some* cases it might work, but the sleazy, lowlife spammer who hijacks peoples' computers to send porn emails is not actually going to honor your opt-out request; he's going to use it to verify that he's found a valid email address. Or he's going to lead you to a web site where he will try to install another trojan. There are, indeed, some email advertisers who follow the law and provide functional opt-out procedures, but in my opinion, the potential risk is greater than the reward.